Great idea, looks really nice. You might want to check the tramming though, you can clearly see the ridges the endmill left (or was it on purpose as a design element?).
Yes, definitely need to look at tramming, but I did not mind the effect on this design.
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Might want to think about a dust collection. 
I actually really like this setup. Maybe have a few spare pieces of Track around to use at the far edges for larger pieces, and this seems pretty sweet.
Getting the impression that you don’t appreciate cnc glitter… 
Just had to get a new shop vac myself. Wore out the old one
I have been struggling with z-clearance lately after I started using some new clamps. When I first built my MPCNC, using the calculator default of ~80mm seemed like a lot of clearance and I read a lot on the forum about not wanting to go too high with the legs due to stability. Recently I started looking at dust collection options and most of the versions I have seen have the tubes come under the core so that it does not give up any cutting area. The way my Primo is currently set up, this would not work for me unless I use really long bits and shallow cuts. I did a quick mock up to try to understand why I am challenged for Z- travel. This helped me see that the designed travel is to the table and after adding the spoilboard, a 3/4" board to cut, clamps that go above the board I am at 20-25mm of usable travel which is barely enough to cut through the 3/4" board.
I am looking for some help to first make sure I did not do something wrong with my setup and second understand how others are addressing this and if there are other solutions I am not thinking about. I can think of several ways to improve this, but I don’t like most of them:
- Cut a hole in my table to recess the spoilboard. This would add 19mm.
- Use clamps that don’t go above the surface of the board. I was using cam clamps with inserts before and they worked well, but took more time to set up, were sometimes came loose with vibration and often lifted the board up off the surface slightly. I have also screwed down the board and used painters tape and glue. I like the current clamps best so far, but there are always trade-offs.
- Lengthen the legs
Hopefully I am missing something easy here because none of these options are my favorite.
Put the legs on strips of MDF, this gives you the height you need, you can see it here for instance: MPCNC Primo Schneewittchen Reanimated - Oldenburg, Germany
I had built mine on top of an old dining table. To compensate for the thickness of the spoil board on top of the table, i replaced the leg tubes with ones cut 3/4" longer. This raised the whole machine up and worked beautifully.
If I were to add MDF strips, is it as easy as unscrewing the legs, adding the strips, and screwing the legs back in (making sure they are square)? Or will more disassembly be required?
As easy as that. 
I made a prototype dust collection system that mounts to the core and is adjustable. It seems to work pretty well, but I was annoyed by the high price of vacuum hose and found some drain hose at my local hardware store. Don’t make the same mistake. It creates an ear-piercing whistle, so I have only run it briefly (all the kapton tape was my attempt to seal things up to isolate the whistle to no avail). Thanks to @stevempotter for his design that gave me a lot of the ideas. One thing I was trying to do was minimize the profiles so I would not use up z travel. It also has a clear magnetic cover so you can see the bit and it also makes bit changes easier. One other cool thing I found on this project was an openscad parametric hose fitting file. I have never used openscad, but I was able to get this up and running in <30mins. It takes a while to figure out all of the parameters, but the flexibility and range of different fittings you can make is cool. Everything from square nozzles, any angle elbow, reducers, Y-fittings and magnetic and flange connections. I only designed the dust shoe and the two bottom rectangular pipes. The rest were made with this openscad file: Printables
4 Likes
Working on some vcarve inlays. Still have some work to do to get rid of the gaps, but the process is not as hard as I thought it would be. These are 2.7 mm deep. The first two I did in one pass with a 60deg v-bit and the last one (pikachu) was two passes with a 30 deg v-bit.
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I am doing some upgrades (More info/pictures to come as I progress). I am switching to DOM steel pipe and reprinting most of the parts with CF-PLA to try to add some stiffness and reduce the chattering. While I was disassembling, I noticed that all of the steppers were slightly loose. I am not sure if this is a problem or not, but should these screws use locktite? I think everything else on the system is either a locknut, or locktite is recommended, but I did not see this on the instructions for the stepper mounts.
You can use blue loctite for those screws and the grub screws holding the pulleys to the stepper shaft. Had your trucks cracked? Mine cracked along the print layers about the mid point of the truck near the motor on the under side. They were printed on a prusa with a very small nozzle though and while they were very high quality and beautiful prints, that setup tends to be less robust than a larger diameter nozzle with a thicker layer, but uglier print.
I have one truck that has a line all the way around it, but it is not separating, so not sure if it is a crack or not. I used a mix of 0.4mm and 0.6mm nozzles on two different printers on my original build. One thing I noticed is the 0.6mm nozzle did not do a good job on the holes and in many cases the bolts would not slip through without threading them in. I got a Bambu X1 carbon earlier this year and have reprinted everything using 0.4mm nozzle and all tolerances seem really good. I used CF-PLA for the trucks and core and some other pieces. CF-PLA comes out looking amazing, almost no layer lines. Hopefully it will add some strength and stiffness.
Quick question: while I am rebuilding, is there any reason to replace the belts while I have everything apart?
I would say no reason. The belts aren’t typically the issue. Do clean the smooth idlers though as they can gather stuff off the back of the belt. Clean the outsides of the bearings as they will pick up junk off the conduit or pipe. Wipe down the conduit/pipes and reassemble systematically with the new parts.